Attachment for lift truck



June 19, 1962 M. J. DRACKETT ETAL 3,039,635

ATTACHMENT FOR LIFT TRUCK SSheets-Sheet 1 Filed Nov. 26, 1957 I fw June 19, 1962 M. J. DRACKETT ETAL 3,039,635

ATTACHMENT FOR LIFT TRUCK Filed Nov. 26, 1957 5 Sheets-Sheet 2 INVENTORS. MYRON J. DRACKETT LESTER K. JENSEN GLENN JOHNSON JR.

ATTY.

June 19, 1962 M. J. DRACKETT ETAL 3,039,535

ATTACHMENT FOR LIFT TRUCK 5 Sheets-Sheet 5 Filed Nov. 26, 1957 IO l (l2 "l, l ie: f l l 1 l f I [9 2 /l 1 f Il l /l I l l l LJ l `l INVENTORS.

MYRON J. DRACKETT LESTER K. JENSEN GLENN JOHNSON JR.

ATTY.

it rates 3,039,635 Patented June 19, 1962 free 3,639,635 ATTACWEN'I EUR LIFT TRUCK Myron Il. Drackett, Lester K. dansen, and Glenn Johnson, Jr., Bettie Creek, Mich., assigner-s to Clark Equipment Company, a corporation of Michigan .Filed Nov. 26, 1957, Ser. No. 69%051 11 Claims. (Ci. Zhi-514) Our invention relates to an article handling attachment for lift trucks and more particularly yto an improved attachment device which is capable of storing and unloading an article in and from an elevated position by moving the article vertically while tipping it from ay posi-Y tion of rest on one side thereof to a position of rest on another side thereof.

By means of our invention we are able to handle certain types of articles in the aforementioned manner by extremely novel and relatively simple, low cost mechanism. In handling certain types of articles in the above manner, storage space may be utilized more eiciently than has generally been the case. d

In carrying out our invention we provide in combination with an elevatable load support means, as fork tines of anindustrial lift truck, pivoted means associated with the load support means for enabling an article carried by the load support means to be tipped from a vertical to an elevated horizontal position or vice-versa, for example, during vertical movement of the load support means, and load l'clamping means cooper'able withthe load support and pivoted means for stabilizing an article supported by the load support means. In addition, We provide means for initiating tipping movement of the article on load support means.

Our device constitutes a significant improvement over the device disclosed and claimed in US. Patent No. 2,799,417, issued to lohn P. Morrell on July 16, 1957, for carrying out such operations as aforesaid. f

It is a principal object of this invention to provide generally improved, simplified and low cost mechanism for raising a carton, box or other `article to a desired height and then releasing the carton from article engaging means `and tipping the article against the side of another article, following which lthe first named article is yfurther raised and tipped to lie on one side thereof atop the last named article.

A further important object of this invention is to provide improved mechanism for first grasping the upper and lower sides of an article that is lying on an elevated horizontal surface, then pulling the article away from its position on said surface until it will tilt by gravity, and nally proceeding to lower the article to a vertical position on a floor, the article being supported during this transition from horizontal to vertical position by improved load support means of a lift truck.

It is a feature of the invention to provide a load handling attachment for lift trucks which includes pivoted means associated with the load support means capable of remaining in full frictional engagement with one side of an article during elevating movement of the article on the load support from Ia vertical to a horizontal position,

It is another feature of the invention to provide in association with load support means of a lift truck extensible means for tipping a carton, box or like object carried 4by the load support means from a vertical toward av horizontal position.

Other objects and advantages of the invention will be apparent in view of the following detailed description taken in conjunction with the drawings, wherein:

FIGURE l is a perspective View of the frontportion of an industrial lift truck which embodies our invention;

FIGURE 2 is a View in side elevation of that portion of FIGURE l which embodies lour invention;

FIGURE 3 is an enlarged detail view in side elevation of the front portion of one of the fork tines shown in FIGURE 2; j

FIGURE 4 is a plan View of FIGURE 3;

FIGURESVS, 6 and 7 are schematic views of certain steps in the operation of our device during the loading of a carton or box from a loweredvvertical position to an elevated horizontal position atop other cartons or boxes; and

FIGURES 8 and 9 are schematic views of certain steps in the operation of our device during transfer of a box from an elevated horizontal position to a lowered vertical position. i y Referring now in detail to the drawings, an industrial lift truck of well known type is shown generally at numeral 10 (FIGURE 5) and comprises generally a body portion 12 which is mounted upon a vehicle frame, not shown, said frame being suitably connected to the axle of front drive wheels, one of which is shown at numeral 14, and to a pair of rear steerwheels i5. An operators station is illustrated generally at 16 and includes a steer wheel 18 and a plurality of controlsfor operating the truck and mechanism to be described which isA associated therewith.

Located forwardly of the front axle and adjacent the drive -wheels i4 is the usual telescoping mast construction 22 which consists generally of a pair of laterally spaced vertical channel members 24 which are pivotally connected ina well known manner to the drive axle, and an 'inner slide structure 26 mounted for telescoping movement within the channels 24. A pair of laterally spaced hydraulic piston and cylinder assemblies, one of which is shown at numeral 28, are pivotally connected at the cylinder ends thereof to the truck frame and at the rod ends thereof to bracket means 30 for tilting the mast construction 22 in either direction on the drive axle housing.

An elevatable carriage assembly'32 comprises a pair of vertically spaced transversely extending bars 34 which are connected in well known manner to the inner slide structure 26 by a pair of laterally spaced bracket and roller assemblies, one of which is shown somewhat schematically in FIGURE 2 at numeral 36, for guided vertical movement in the mast structure relative to inner slide 26 and channel members 24. An hydraulic hoist motor 38 is mounted tothe base of the mast structure at its lower end and to the inner slide 26 by means of a bracket 4i) at its rod end. Sprockets and chains, not shown, may be of the usual construction for operatively connecting the rod end of the motor 38 to the carriage 32 for raising and lowering the carriage relative to the mast assembly.

A pair of laterally spaced fork tines 42 are detachably connected by brackets 43 to the upper bar member 34.

Mounted at the outer end of each tine is a T-shaped` member 44 having a wedge shaped forward pontion 46 each said member being mounted 'for pivotal movement upon la transverse pin or shaft 48 which is supported at its oposite ends in transverse openings Sii formed in leg portions 52 of a U-shaped end portion 54 of each tine. The base portion of each T-shaped member is received in the pocket of each U-shaped portion 54, each of said T- shaped members being freely rotatable in a clockwise direction from the horizontal poistion thereof illustrated in FIGURES l-4. A projection 56 extends rearwardly from the base portion of each member 44 and is adapted to abut a complementary projection 58 formed along the base of each pontion 54 when the members 44 Kare in horizontal position, thus, limiting movement thereof in a counterclockwise direction. The weight ydistribution of such that said members normally reside in the position 3 shown in FIGURES l-4. If desired, a plurality of rows of upwardly extending projections 60 may be secured to the base portion of each 'T-shaped member for insuring gripping engagement between the upper surface thereof and `one side of are'arton, box or other article -in -a manner to be described. A friction material or equivalent means can, of course, be provided in lieu of projections 60, if desired, for the above named purpose. y

-A vertically extending -plate member l62 may be secured to the bar members 34 between` the fork tines for supporting .a ftelescoping clamp mechanism 6ft. The clamp mechanism, las shown, comprises a pair of -laterally spaced channel members 66 which `are secured along a portion of rth'e rear legs thereof to the front surface of plate 62, and which are secured together at the bottoms thereof by ia transverse plate 68. If desired, the Vrear legs of ithe channel members 66 may be secured directly to rbar members 34, thereby dispensing with the plate 62. Nested for sliding movement within the channels j66 are two pairs of laterally spaced channel members 7 ti and 7.1. An hydraulic hoist motor 72 is secured at the cylinder end thereof to plate 68, the extensible rod 7d being connected as by bolts 76 lto a transverse bar 77 which is secured at its opposite ends toinner slide members 7h. Pairs of abutment members 78 and 78' are secured to the edges of the legs of each movable channel member 71 in the lower and upper sections thereof, respectively, whereas pairs of abutment Imembers 79 `are secured t'o the edges of the legs. of each movable channel member 70 adjacent the lower ends thereof, and abutment members 79 are secured to the edges of the legs of each stationary channel member 66 in the upper Vsection thereof. When the channel assembly of clamp mechanism 64 is lowered (FIGURE l) members 78 -and 79 lie-adjacent each other 'near the lower end 'of the assembly and members 78' and 79 lie .adjacent each other near the upper end of the assembly. If the hoist motor v'72 is pressurized to extend the channel assembly, inner slide members 70 first rise alone with piston rod 74 until members 79 Contact members 78', subsequent to which intermediate slide members 71 rise with members 70 until members '7d abut members 79', Iat which time extension of the channel assembly ceases. y

Secured to the central section of bar member 77 is a pair of parallel, forwardly extending clamp pad support members Si) which pivotally support at the forward ends thereof a clamp padSZ. -The clamp pad is pivotally connected by Ia pair of laterally spaced brackets 86 to a transverse pin 84 which extends between members 8d. The hoist motor 72 is double acting, whereby pressure iluid from a source, not shown, may be introduced into either end of the cylinder 72 to raise and lower clamp pad S2 with inner slide members 70 as aforesaid.

Mounted above `a transverse mast brace member 9i) adjacent the upper end of each channel member 24 is a generally rearwardly and upwardly extending cylinder support bracket 92 which includes laterally extending bracket portions 9A projecting from the corners thereof for supporting an hydraulic cylinder and piston assembly 96. The cylinders of assemblies 96 may be secured, as by welding, to the bracket portions 94. Pivotally connected to the end of the piston rod of each cylinder assembly is a pusher pad member 9S. vWhen the piston rods are retracted, the pad members 98 are located adjacent the forward leg portions of channel members 24, but are adapted to be extended considerably forwardly thereof with the piston rods for Ia purpose 'to be described.

Referring now particularly to FIGURES -7, we have illustrated our invention in certain stages of operation during vthe transfer of `a carton of material 100 from a vertical posi-tion at floor level to a raised horizontal position atop a plurality of upstanding containers 102. Initially the fork truck engages the container 100 (FIGURE 5), following la raising of clamp pad 82 with extension of the channel assembly 70, '71 to clear the top` of the container, by moving fork tines 42 under the bottom surface of the container until the one side surface thereof abuts or is closely :adjacent to the forward legs of channel members 66. tIn order to facilitate such engagement, the `rods of cylinder assemblies 96 may be extended to bring pads 9S into engagement with the facing side of the container so as to tip the container forwardly, thereby making easy fthe entry of the fork tines beneath the container. Of course, the relative lengths of the cylinder assemblies 96 and the fork tines may be varied in manufacture as desired. Following such engagement the cylinder 72 lis energized to lower clamp pad'82 until it `abuts a portion of the top surface of the container, whereafter the main hoist motor 3S is energized to elevate the container with carriage assembly 32 and clamp assembly 6i in the main mast assembly '22.

The container may then be moved with the truck to any desired location, such as adjacent .the plurality of con'- tainers ltiZ. Now if it 'be desired to place the container 100 in the position shown in FIGURE 7 atop containers 11%2, the fork tines 42 and associated structure may .be raised in mast assembly 22 to a convenient elevation relative to the containers 162, such as shown in FIGURE 6, following which the 'cylinder 72 is energized tov elevate clamp pad 82 and release container 100. Preferably, the fork tines are of such length that the center of gravity of a normal load thereon will be located beyond the ends 'of the tines so that the load will tip forwardly upon release thereof by clamp pad S2. However, whenever l necessary or desirable, the cylinder assemblies 96 may be pressurized to extend the piston rods thereof in order to engage pads 9S with the facing surface of the container `and forcibly tip the container forwardly. The pad members 9S are pivoted so that they can accommodate to irregularities in the containers. The container tips or is tipped until a portion of the `forward surface thereof rests against the adjacent upper edge of the nearest container 102 (FIGURE 6).

As the container 10o tips to the aforementioned position it will be seen that the T-shaped members 44 will be caused thereby to pivot on shaft 48 in a clockwise direction and be maintained in full surface engagement with the bottom side of the container.

The fork tines .and associated structure are then raised in mast assembly 22 which causes the container 100 to slide .along the aforementioned edge of container 102 simultaneously with upward and further forward tipping movement thereof. When the container 190 reaches a position at which its center of gravity is located forward of the facing side of container 102, it will tip to a horizontal position by the action of gravity. During such movement, the T-shaped members 44 will pivot as required to maintain engagement with the one side of the container.

The distance of the truck from containers 102 may be adjusted so that the terminal tipping movement of the container to a horizontal position is relatively slow, thereby avoiding possible damage to the containers. If the truck is `too close to the containers 102 during the terminal phase of tipping it will be apparent that the container will be caused to tip by gravity through a relatively large angle, and the resulting impact between containers 100 and 102 may damage them. On the other hand, if the truck is too distant from the nearest container 102, the terminal phase of tipping may be dependent solely on 'engagement of pad members 44 with the container during raising of the fork tines. We prefer, therefore, that the terminal phase of tipping the container be performed with the truck located ,at an intermediate distance wherein the container will be tipped by gravity through a relatively small angle.

After the container is located in horizontal elevated position (FIGURE 7) the truck may be driven forwardly to push the container by means 'of the T-shaped members into a position wherein the one side surface of the container is in full engagement with the upper surfaces of containers v102 and the facing-surface is substantially in ythe plane of the one side surface of the nearest container 102 (dotted lines, FIGURE 8).

As will be apparent from the above, our invention is particularly useful in storage areas where Isufficient vertical storage space is available for storing 'elevated horizontally disposed containers, but where such space is insuflcient for storing such containers in elevated vertical position. Of course, container 100 may be stored in horizontal position atop more than one tier of containers 102,

assuming sufficient vertical storage space and adequate range of lift of mast assembly 22.

In order to remove the container 1% from the position i thereof shown in dotted linesin FlGURE 8, the truck is initially moved into adjacency with the containers while the fork tines are elevated to the plane of the parting line i between containers 100 and 102 so that they may be wedged therebetween. For the latter purpose the wedge shaped portion 46 of each T-shaped member 44 is particularly useful in facilitating entry of the tines between the containers. Following substantially full engagement of .the fork tines with the one side of the containerlti, clamp pad S2 may be lowered into clamping engagement with the upper side of the container. Thereafter, the truck may be backed away from containers 102 in order to pull container 100 away from its rest position on containers 2, as shown in solid lines in FIGURE 8V The truck continues to back away until the center of gravity of container 100 is located beyond the nearest surface of container 102, whereby the container 109 will tip in a counterclockwise direction under the influence of gravity upon lowering movement of the fork tines. After the container 10i) has been pulled a sufficient distance away from its position of rest on containers 162, the clamp pad 82 is elevated to release its grip on the container. The fork tines and associated structure are next lowered in mast assembly 22, thereby permitting the container 100m tip in a counterclockwise direction about the upper edge of container 162. During such tipping action the lower forward edge of container 100 slides along the fork tines to a position beyond the pivot axes of T-shaped members 44, at which time the T-shaped members pivot into engagement with the bottom surface of the container. The container may then be lowered to near Ifloor level with the fork tines (FIGURE 9), during which movement the one surface of container 100 slides along the upper facing edge of container 102. When the container 100 is near floor level, the truck may be driven toward containers 102 to tip the container 100` into vertical position on the fork tines, following which clamp pad 82 may be lowered to engage the container.

It will be noted that during such lowering movement of the container as aforesaid, the container will be supported on T-shaped members 44 and the upper facing edge of adjacent container 102 in much the same manner as during elevating movement thereof. The major portion of the weight of container `100 is normally supported by the fork tines during lowering movement thereof, and it will be apparent that the upper edge of container 102' functions primarily as a pivot `for container 100.

"From the foregoing description taken in conjuction with the drawings, it will now be seen that we have provided an extremely novel attachment device for use with lift trucks which is capable of performing certain materials handling operations in a much improved manner.

While only one speci-tic embodiment of our invention has been disclosed in detail, it .will be apparent to persons skilled in the art that numerous changes and modifications may be made in the construction, design and arrangement of parts without departing from the scope of the invention.

We claim:

1. An attachment for industrial lift trucks having a power actuated telescoping mast assembly located adjacent one end thereof, comprising forwardly extending load support means mounted `for vertical movement onextensible means to tip the load forwardly vof the truck and into abutment with a portion of said floor supported member, following which elevation of the load support 4meansin the lifting mast causes said pivot means to pivot lso as to maintain engagement with the bottom surface of the load during continued tipping movement thereof until said load rests horizontally atop the elevated surface of said iloor supported member.

2. An attachment as claimed in claim l wherein said pivot means is mounted for pivotal movement to a vertical position of full engagement with said bottom surface of said load when said load is in said elevated horizontal position, whereby said pivot means may be utilized rto vmove the load horizontally along said elevated surface during movement of the truck toward lsaid door supported member.`

3. An attachment as claimed in claim l wherein said load Support means comprises a pair of laterally spaced and forwardly extending tines, and 1said pivot means is pivotally connected to said tines adjacent the forward ends thereof.

4. An attachment as claimed in claim l wherein said load support means is relatively long Iin length, aand said pivot means is relatively short in length,

5. An attachment for -use with lift trucks having `an extensible mast assembly located adjacent one end thereof and forwardly extending load support means actuatable vertically in said mast assembly, comprising relatively short load engaging means mounted on the forward end of the load support means and extending forwardly of and in the plane of the load support means for pivotal load engaging movement relative thereto, and load clamping means associated with the load support means for clamping engagement with and disengagement from a load carried by the -load support means, said load support means and clamping means being cooperable to engage therebetween an elongated horizontal load which is supported upon an elevated surface and to pull said load away from said surface with rearward movement of the truck until the load can tip by gravity toward upright position upon subsequent lowering movement of the load support means in the lifting mast, said clamping means being thereupon actuated to release its hold on said load 'and said load support means being thereafter lowered to permit the load to tip rearwardly about the adjacent upper edge of said elevated surface until the load is moved thereby to a Isubstantially vertical floor level position, said load engaging means being pivoted by the weight of the load into continuous supporting position with the bottom surface of the load during concurrent lowering and tipping movement thereof on the load support means.

6. An attachment for use with a lift truck having a power actuated lifting mast assembly located at the forward end thereof, comprising the combination of extensible motor means supported by the lifting mast, rst pad means supported by the motor means and extensible therewith forwardly of the lifting mast, a pair of fork tines supported for vertical movement on the lifting mast immediately adjacent said mast, power actuated and independently vertically movable clamping means supported for elevation with the fork tines on the lifting mast immediately adjacent said mast and adapted to hold a load on the fork tines, and second pad means pivotally mounted on the forward end of each fork tine, said first extensible pad means, clamping lmeans and fork tines being cooperable to engage, tip forwardly and raise an lelongated load from a non-elevated vertical position to an elevated horizontal position atop a raised surface, and said second pivoted pad means pivoting throughout movement of the load Yfrom said Vertical to said horizontal positionto maintain engagement with the bottom surface of the load.

7. For use with va lift truck having -a mast assembly connected tothe truck at one end thereof and a power hoist mechanism lassociated -therewith for elevating loads thereon, a forwardly extending load` support means operatively connected to the lifting mast for vertical movement relative thereto in close longitudinal proximity thereto, clamping means connected to the load support means and movable vertically independently thereof for holding an elongated upright load on the load support means, Said load support means being relatively short in length so that such al load supported thereby will tip forfork tines and lifting carriage from a ground level position through a forwardly tipped position to'a horizontal position atop elevated surface, said pair of pivot members pivoting forwardly out -of ush relation with the fork tines to a position substantiallyI at right angles thereto Wardly thereof by gravity upon Verticalrinovement yof Vthe clamping means to release its hold on the load, and pad means connected to yand `extending forwardly of and in the plane of the load support means Iand pivotable longitudinally forwardly thereof to maintain engagement with the bottom surface of said load as the load tips forwardly of the load support means, said load being movable vertically by the load support and pivoted pad means through a forwardly tipped to an elongated horizontal position atop 'an elevated surface, during which movement said pad means pivots to maintain continuous engagement with said bottom load surface.

8. An attachment las claimed in claim 7 wherein the load support means comprises a pair of laterally Aspaced fork tines, the clamping means includes a vertically extensible mast construction located intermediate vthe fork tines, and the pivoted pad means is mounted to extend forwardly of the forward tips of the fork tines.

9. For use with a lift truck having a vertically movable power actuated lifting carriage located adjacent one end thereof, the combination comprising a pair of laterally spaced forwardly extending forkl tines connected to the lifting carriage for vertical movement therewith, a .pair of in maintaining engagement with the bottom surface of the load during such movement, and said pivot members being adapted to subsequently move the load horizontally on said elevated surface with forward movement of the truck.

V10. A device as claimed `in claim 9 wherein means are associated with the load engaging surface of each pivot member 'for firmly engaging said bottom load surface to avoid slippage during such movement of the load.

11. A device a-s claimed in claim 9 wherein Vsaid fork tines are generally U-shaped at the forward ends thereof and said pivot members are generally T-shaped with the leg portions thereof being pivotable into the respective pocket portions of the Urshaped fork tine ends in which position said pivot members are substantially flush with said fork tines.

AReferences Cited in the file 'of this patent UNITED STATES PATENTS 

